Printing and publishing, along with other forms of text and graphics presentation such as cathode ray tube displays and the like, have been accompanied by corresponding advances in the typographic art. This art is based upon the original typesetting art; it relates to the style, arrangement and appearance of so-called typeset matter. Typography not only includes the selection of text, it also relates to the arrangement of text and graphics in a particular presentation. Making such arrangements is often called composing and formatting.
A brief history of printing, typography and typesetting, including composition, is set forth in a book entitled Pocket Pal, of which the 12th edition was published in March, 1979 by the International Paper Company, 220 East 42nd Street, New York, N.Y. 10017. Typography has evolved from hand typesetting to electronic photocomposers and printers. In these latter generations of machines, often referred to as the third generation of photocomposing, characters or symbols, as well as graphics, are formed by a series of minute dots or lines. The electronically-formed image, such as by a laser beam, is transferred to photographic material, to electrophotographic surface of an electrophotographic printer or other suitable image-forming surface. Such minute dots or lines are often formed as a raster or rectangular array of dots which are defined by digital signals; hence, this type of printing and typesetting is often referred to as digitized typesetting or printing. Such advanced machines allow the storage of text symbols and the control for using those symbols in electronic memories, such as found with high-speed electronic digital computers.
Even before the advent of all-electronic printers and typesetters, digital computers were used in the typographic art for providing formatted and composed text and graphics to earlier generation photocomposing machines. That is, a programmed digital computer received text and graphics data in the form of digital signals. These digital signals were manipulated in accordance with programs of the digital computer. The digital computer then provided the manipulated signals to the printer or photocomposer such that the latter elements visually presented the text and graphics data in accordance with computer program controlled composition and format parameters. Such automation of typography greatly relieves the burden on the typographer and hence provides a more efficient and versatile visual presentation that can be as aesthetically pleasing as hand-set type. An example of an early typographic composing computer program is TEXT-90, a computer program executed by the IBM 7090 digital computer system. The 7090 system was attached to a photocomposer which created the visual presentation of the text and graphics formatted by TEXT-90. TEXT-90, inter alia, manipulated the digital signals representing the text and graphics to build text lines and pages. Additionally, where text was to be presented in two side-by-side columns, such as found commonly in English language dictionaries and the like, the vertical depths of those columns were justified or balanced. This was achieved in TEXT-90 by always making the depth of a shorter one of the columns equal to the vertical depth of the longest column. That is, to achieve vertical justification, a column was always expanded. This action in text presentation resulted in a slight spatial increase between the successive lines of text when the shorter column was expanded to the longer column. Such expansion was also created by adding vertical "skips" between lines. The number and size of skips in a column were determined by the difference between the depth of the longer column and the depth of the shorter column. The skips, i.e. vertical background padding, were generated by scanning for headnotes (titles); additional blank for vertical space justification was preferably added at such headnotes.
Following TEXT-90, more advanced typographic-related computer programs, including the PRINTEXT/370 and COMPOSITION/360 programs as well as Document Composition Facility (DCF), also included text page and column controls. The concept of a logical page was introduced. A set of digital signals provided a page definition which specified the dimensions of the page to be formatted. A column definition defined the number and width of columns and the space between the columns (gutters). A new page command caused subsequently received text representing digital signals to be formatted as a new page of text. In a similar manner, a new column command caused subsequently received text representing digital signals to be formatted in a new column. Programmed column processing specified whether the text was to be distributed among a plurality of columns and whether blank space was to be added in order to balance column lengths or depths. That is, vertical justification in COMPOSITION/360 was achieved by adding unprinted areas for lengthening a shorter column to the depth or length of a longer column. The programmed controls also permitted presenting text and graphics without vertical justification.
In the latter programs, column justification was a two-step process. A first step was to distribute text and graphics between the various columns within a specified number of columns to make the column depth as nearly equal as possible. Such balancing distribution was selectively initiated within the program by a suitable command from a user. The second step was a spacing step which determined whether or not additional blank or unprinted space was to be added to short columns to balance the depths of the columns. The spacing steps were performed with or without a preceding text distribution step. When column distribution was specified, the text and graphics were distributed amongst a plurality of columns. Column distribution was specified by a so-called "PAGE REG," "NEW PAGE," "PAGE DEFINITION" or "COLUMN DEFINITION" text control word being encountered or when the end of the document was defined. On pages having a plurality of columns, balancing was performed on all of the columns in a balanceable set after the distribution of the text or graphics had been performed. Under selective control, if the text and graphics were not distributed among the various columns, then the columns could be balanced to a maximum column depth (which might or might not be equal to the longest column of text, i.e. could be to a page length for example). These programs distributed data among the various text columns in a single pass of programming execution.
With all of the above-described automatic typographic machine-implemented procedures, the quality of text and graphics presentation has continually been enhanced, such as described in the book Phototypesetting: A Design Manual, by James Craig, published by Watson-Guptill Publications, 1515 Broadway, New York, N.Y. 10036. Prior to the all-electronic printers, such as the electrophotographic printers, text was presented on a line-by-line basis; that is, a mechanism in the printer moved paper receiving the printed matter a distance equal to the center-to-center spacing of successive lines of text. The advent of the all-electronic printer did away with some constraints on the typographic art in that a page of data is represented by a rectangular array of print elements (PELs) which are individually addressable using digital computer addressing techniques. In other words, the all-electronic printer is programmed and controlled in the same way that a cathode ray tube is controlled for visually presenting text and graphics data. It is to this enhancement in document presentation that the present invention is most advantageously employed. The addressability of each print element of which a symbol in a given font may include a subraster array of 150 by 200 PELs, for example, enables expansion and compression of the text representing symbols as well as scanning all forms of graphics data. These enhancements create a demand for a more pleasing and aesthetic presentation of text in side-by-side column format. To this end, the present invention is directed to the automatic text and graphics composing and formatting of side-by-side columns which substantially enhance the visual presentation of text and graphics. All of this is achieved without operator intervention except for the supplying of formatting commands. Such enhancement obviates the need for operator selection on an interactive basis of column control, such as set forth in U.S. Pat. Nos. 3,952,852 and 4,207,011. This invention also enables the text and graphics composing and formatting at the print element, or PEL level, for all-points-addressable printers as well as to a line printer with programmed vertical formatting as set forth in U.S. Pat. No. 4,282,583.